245/40R15 tire size

A 245/40R15 tire is 22.72 inches (577.0 mm) tall, 9.65 in (245 mm) wide and fits a 15-inch wheel. In inch notation it is roughly a 22.7x9.6R15.

245/40R15 dimensions
Overall diameter	22.72 in	577.0 mm
Section width	9.65 in	245 mm
Sidewall height	3.86 in	98.0 mm
Circumference	71.37 in	1,813 mm
Revolutions	887.8 per mile	551.7 per km
Rim diameter	15 in	381.0 mm

Compare 245/40R15 with another size

Current size

New size

Speed in mphkm/h

Overall diameter difference

−1.79%

60 mph on the speedometer = 58.9 mph actual

Within the ±3 % diameter range most tire fitters accept.

Ground clearance: −5.1 mm (−0.20 in)
Revolutions: 888 → 904 per mile

245/40R15 215/55R13

Side-by-side dimensions

	Current	New	Difference	%
Diameter	22.72 in	22.31 in	−0.41 in	−1.79%
Diameter	577.0 mm	566.7 mm	−10.3 mm	−1.79%
Width	9.65 in	8.46 in	−1.18 in	−12.24%
Width	245.0 mm	215.0 mm	−30.0 mm	−12.24%
Sidewall	3.86 in	4.66 in	+0.80 in	+20.66%
Sidewall	98.0 mm	118.3 mm	+20.3 mm	+20.66%
Circumference	71.37 in	70.09 in	−1.27 in	−1.79%
Revs per mile	887.8	904.0	+16.1	+1.82%

Speedometer error

Speedometer shows	Actual speed	Difference
20 mph	19.6 mph	−0.4 mph
30 mph	29.5 mph	−0.5 mph
40 mph	39.3 mph	−0.7 mph
50 mph	49.1 mph	−0.9 mph
60 mph	58.9 mph	−1.1 mph
70 mph	68.8 mph	−1.2 mph
80 mph	78.6 mph	−1.4 mph

Plus and minus sizes for 245/40R15

Size	Wheel	Diameter	Difference
215/55R13	Minus 2 (13 in)	22.31 in	−1.79%
215/40R16	Plus 1 (16 in)	22.77 in	+0.24%
225/35R17	Plus 2 (17 in)	23.20 in	+2.13%

Vehicles approved with 245/40R15 tires

Models whose Swiss type approval lists 245/40R15 as a standard or optional size (8 approvals in total). Always check your own vehicle's placard or papers.

Caterham Seven

Source: Swiss Federal Roads Office (FEDRO/ASTRA), open government data. Original data (downloaded 2026-09-29). Data processed by us; errors in processing are ours, not the publisher's.

Nearby 15-inch sizes

225/50R15 (+5.0%)

Reading the 245/40R15 size

245 — section width in millimetres (9.65 in).
40 — aspect ratio: the sidewall is 40 % of the width, 98.0 mm.
R — radial construction (ZR on the sidewall means a high-speed rated radial; the dimensions are the same).
15 — fits a 15-inch diameter wheel.

The load index and speed rating (for example 91V) follow the size on the sidewall. They must meet at least the values on your vehicle's tire placard.